In quantum field theory (QFT) each diamond is endowed with an operator algebra whose Heisenberg evolution between time slices that remain inside the diamond closes on itself. The entanglement entropy of any state on this algebra with the systemThis statement is true for any state on the full algebra for which the integrated stress tensor does not scale with the maximal volume of spacelike slices in the diamond. in any larger diamond, is infinite, but proportional to the area of the holographic screen. It is widely assumed that in a theory of quantum gravity, these infinities will be regularized by the finite Planck length. The CEP simply implements this suggestion and uses the black hole examples to determine the normalization[1]} of the area/entropy relation in terms of the Planck area. The CEP has been "derived"[2]} by Euclidean path integral methods similar to those[3]} used to compute black hole entropy.
